An object is placed 30 cm from a convex lens of focal length 20 cm. How far from the lens is the real image formed?
Answer and explanation
Correct answer: B. 60 cm
- Step 1: Lens formula: .
- Step 2: .
- Step 3: cm.
Answer
60 cm.
Why not the others: 10 cm: it subtracts the focal length from the object distance. 50 cm: it adds the distances. 12 cm: it uses instead of .
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